Biochemical Genetics

Biochemical genetics involves diagnosing and treating metabolic diseases. These are problems with how the body makes, breaks down or uses proteins, fats or carbohydrates. They are caused by genes that are not normal and cannot make the enzymes the body needs. (Enzymes are found in the blood, organs, saliva and other parts of the body. They are important to all bodily functions.)

These diseases are called inborn errors of metabolism. Our team helps to diagnose, monitor and manage these diseases. We work closely with doctors in other departments at Seattle Children’s and in our Genetics Lab. Most of our patients have complex health problems. They need coordinated, long-term care from a team of experts, like ours.

Diagnosing and treating metabolic diseases early can improve a child’s quality of life. The Washington State Department of Health screens newborns for these diseases. We work with them to provide any follow-up genetic testing and care that newborns need.

Our program is part of the American Board of Medical Genetics–certified training program at the University of Washington. Another name for this area of genetics is metabolic genetics.

Conditions We Treat

Hundreds of genetic disorders relate to metabolism. Six kinds are shown below. We treat these and other conditions.

Children with these disorders cannot use fats for energy. This can lead to low blood sugar, muscle weakness and heart problems. Medicines and special diets can treat many of these disorders. Examples are medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency and very long–chain acyl-coenzyme A dehydrogenase (VLCAD) deficiency.

Many building blocks of the body, such as proteins, fats and other molecules, need to have sugars attached to them to work properly. Individuals with congenital disorders of glycosylation (CDG) cannot attach these sugars or sugar chains properly. Children or adults with CDG may have problems with growth and learning, and the disorder may affect many parts of the body, including the brain, nerves, muscles, liver and immune system. Examples of CDGs include PMM2-CDG, ALG1-CDG, PIGT-CDG and MPI-CDG. Additionally, individuals may also have NGLY1-CDDG, a disorder where the body has trouble taking off sugar chains from some proteins.

These disorders are due to a buildup of complex sugars within small sections inside cells. These sections are called lysosomes. The buildup makes the cells swell and become damaged so they do not work normally. All lysosomal storage disorders (LSDs) affect different body systems and cause different symptoms. Some LSDs can be treated. Examples of LSDs are Gaucher disease, Hunter syndrome (MPS II), glycogen storage disease type II (Pompe disease) and Tay-Sachs disease.

These disorders affect how the body makes energy. They can involve many body systems. Most often they involve the heart, brain and muscles. Examples are mitochondrial encephalomyopathy lactic acidosis and strokelike episode (MELAS), Alpers disease, Barth syndrome and respiratory chain complex deficiency.

Children with these disorders cannot properly use protein for energy. This can cause toxic acids to build up in their bodies. They may then have problems with growth, learning and overall health. Medicines and special diets can treat many of these disorders. Examples of organic acid disorders are propionic acidemia (PA), methylmalonic acidemia (MMA) and glutaric acidemia types I and II.

Children with these disorders cannot use protein properly for energy. This can cause toxic by-products to build up in their bodies. The buildup can lead to problems with growth, learning and overall health. Medicines and special diets can treat many of these disorders. Examples of urea cycle disorders are ornithine transcarbamylase (OTC) deficiency, argininosuccinic aciduria and citrullinemia.

Children with Wilson disease cannot get rid of extra copper they receive from their diet but do not need. Most children's bodies filter out this extra copper. But for children with Wilson disease, the copper builds up and can damage their liver, brain and other organs. Medicines and diet changes can treat Wilson disease if it is diagnosed early.

Services We Provide

Many children born with metabolic diseases need care and treatment throughout their lives. This helps them to do the best physically and mentally and have the best possible quality of life.

We provide complete diagnostic evaluation. This includes testing for newborns with abornmal Washington state screenings, complete nutritional assessment and long-term metabolic management along with dietary treatments. Genetic counseling is available for children and adults with suspected or diagnosed inborn errors of metabolism.

At Seattle Children's we provide a long-term "medical home" for your child — a place that manages all their care to help them get the most complete care they can. We work closely with other doctors in the clinic and hospital if your child gets sick. We also help other doctors in the Northwest to provide proper care for your child.

Some metabolic diseases happen because a child has an enzyme that is not normal. This causes sugars and proteins to build up in the body. In enzyme replacement therapy (ERT), we give your child the enzyme they need through an intravenous (IV) line. This process is called infusion. ERT treats the symptoms of the disease but does not cure the disease. It is used for some lysosomal storage disorders — Gaucher disease, Fabry disease, MPS I, MPS VI and glycogen storage disease type II (or Pompe disease).

Seattle Children’s complies with applicable federal and other civil rights laws and does not discriminate, exclude people or treat them differently based on race, color, religion (creed), sex, gender identity or expression, sexual orientation, national origin (ancestry), age, disability, or any other status protected by applicable federal, state or local law. Financial assistance for medically necessary services is based on family income and hospital resources and is provided to children under age 21 whose primary residence is in Washington, Alaska, Montana or Idaho.